In late June 2012 a major forest fire – the Waldo Canyon Fire – developed to the northwest of Colorado Springs. The fire covered 29 sq mi, led to the evacuation of 32,000 residents, and destroyed at least 346 homes. It is now regarded as the most destructive fire in Colorado state history.

The Waldo Canyon Fire started on June 23. It was one of a number of forest fires in Colorado fueled by record-breaking hot and dry conditions during the spring and early summer over the state. The fire grew in size for the next few days after the 23rd, but it was not until the late afternoon of June 26 that it suddenly jumped containment lines and quickly spread down the mountain slope on the west side of Colorado Springs into residential neighborhoods destroying many homes. The rapid eastward spread of the fire on this day was a result of a macroburst emanating from a thunderstorm complex that passed to the northwest of Colorado Springs. The origin of this storm system can be traced back to the Rio Grande Mountains in far southwest Colorado. These storms developed in dry, microburst type conditions and generated strong surface outflows throughout their passage across the state. The sequence of meteorological events leading up to the explosive growth of the fire will be reviewed in the talk.